The Price Of Green Electricity

The Denver Post helpfully recaps the per kilowatt hour cost of various green energy sources compared to natural gas and coal. The vast majority of electricity now produced in Colorado comes from coal fired plants.

Photovoltaic arrays cost roughly 20 to 24 cents per kilowatt hour, compared with 13 to 16 cents for concentrating solar power, according to the Golden-based National Renewable Energy Laboratory. Natural-gas power costs an average of 8 to 10 cents, while coal runs about 4 cents.

A solar thermal plant located in New Mexico which would open in 2010 is being contemplated by two major Colorado utilities who are now under heat from the Ritter adminstration and a ballot initiative to generate greener electricity.

Alas, the story does not price out some other important possibilities: new nuclear fission plants, wind, new hydroelectric plants, biomass, and "clean coal" technologies that process coal into a liquid or gaseous form before burning it.

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By the way, Popular Science recently covered another important development in the coal fired power generation process. Someone has come up with a way to recycle fly ash produced by coal fired power plants to make bricks. Fly ash is a major waste product of coal fired plants, which produce hundreds of thousands of tons of the stuff each year, although fly ash is one of the least important pollution products of coal fired plants whose greater menaces are air pollution and the coal mining process. Fly ash bricks, thus, do little to make the coal fired plant any greener itself, but fly ash bricks reduce pollution otherwise generated by the brick making process and reduce construction costs:

The U.S. churns out nine billion clay bricks a year—every one of them an expensive environmental nightmare. They require costly mining and bake in 2,000°F kilns that guzzle fuel and spit out pollutants. And making cement for concrete bricks spews thousands of pounds of poisonous mercury into the air annually.

So Henry Liu built a better brick, one that lasts just as long and puts to use a waste product of coal-power plants—fly ash—that would otherwise fester in a landfill. His bricks solidify under pressure, not extreme heat, so manufacturing them saves energy and costs at least 20 percent less. And because the bricks are molded, they're smoother and more uniform, slashing bricklaying time and labor.

It took eight years and $600,000 (a pittance considering the potential impact of the project) to figure out how to make fly ash bricks structurally sound.

The fly ash brick product also illustrates a more general principle of recycling. The people who recycle wastes are rarely the people who generate it. The notion that wastes have value and can be a separate revenue stream is simply too much for most businesses to come up with by themselves.